3. calculations

In IntCal: Radiocarbon Calibration Curves

require(IntCal)

The IntCal package also provides some functions related to radiocarbon calibration. First there are two functions to calculate radiocarbon ages from pMC values (in this case of a postbomb date):

pMC.age(150, 1)

and the other way round:

age.pMC(-2300, 40)

We can also obtain the calibrated probability distributions from radiocarbon dates, e.g. one of 130 +- 20 C14 BP:

calib.130 <- caldist(130, 20, BCAD=TRUE)
plot(calib.130, type="l")

For reporting purposes, calibrated dates are often reduced to their 95% highest posterior density (hpd) ranges (please report all, not just your favourite one!):

hpd(calib.130)

Want a plot of the radiocarbon and calibrated dates, together with their hpd ranges?

calibrate(130,20)

You can also draw one or more calibrated distributions:

set.seed(123)
dates <- sort(runif(5, 100, 1000))
errors <- .05*dates
depths <- 0:4
labels <- c("my", "very", "own", "simulated", "dates")
draw.dates(dates, errors, depths, BCAD=TRUE, labels=labels, cal.lim=range(dates, 600, 1700))

or add them to an existing plot:

plot(0, type="n", xlim=c(600, 1700), ylim=c(5,-1), xlab="AD", ylab="dates")
draw.dates(dates, errors, depths, BCAD=TRUE, add=TRUE, labels=labels)

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<- prev (plots)

IntCal documentation built on July 12, 2022, 1:05 a.m.